Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Jason A. Williams is active.

Publication


Featured researches published by Jason A. Williams.


The Annals of Thoracic Surgery | 2009

Aortic Root Replacement in 372 Marfan Patients: Evolution of Operative Repair Over 30 Years

Duke E. Cameron; Diane E. Alejo; Nishant D. Patel; Lois U. Nwakanma; Eric S. Weiss; Luca A. Vricella; Harry C. Dietz; Philip J. Spevak; Jason A. Williams; Brian T. Bethea; Torin P. Fitton; Vincent L. Gott

BACKGROUND We reviewed the evolution of practice and late results of aortic root replacement (ARR) in Marfan syndrome patients at our institution. METHODS A retrospective clinical review of Marfan patients undergoing ARR at our institution was performed. Follow-up data were obtained from hospital and office records and from telephone contact with patients or their physicians. RESULTS Between September 1976 and September 2006, 372 Marfan syndrome patients underwent ARR: 269 had a Bentall composite graft, 85 had valve-sparing ARR, 16 had ARR with homografts, and 2 had ARR with porcine xenografts. In the first 24 years of the study, 85% received a Bentall graft; during the last 8 years, 61% had a valve-sparing procedure. There was no operative or hospital mortality among the 327 patients who underwent elective repair; there were 2 deaths among the 45 patients (4.4%) who underwent emergent or urgent operative repair. There were 74 late deaths (70 Bentalls, 2 homograft, and 2 valve-sparing ARRs). The most frequent causes of late death were dissection or rupture of the residual aorta (10 of 74) and arrhythmia (9 of 74). Of the 85 patients who had a valve-sparing procedure, 40 had a David II remodeling operation; there was 1 late death in this group, and 5 patients required late aortic valve replacement for aortic insufficiency. A David I reimplantation procedure using the De Paulis Valsalva graft has been used exclusively since May 2002. All 44 patients in this last group have 0 to 1+ aortic insufficiency. CONCLUSIONS Prophylactic surgical replacement of the ascending aorta in patients with Marfan syndrome has low operative risk and can prevent aortic catastrophe in most patients. Valve-sparing procedures, particularly using the reimplantation technique with the Valsalva graft, show promise but have not yet proven as durable as the Bentall.


The Annals of Thoracic Surgery | 2008

Aortic Root Operations for Marfan Syndrome: A Comparison of the Bentall and Valve-Sparing Procedures

Nishant D. Patel; Eric S. Weiss; Diane E. Alejo; Lois U. Nwakanma; Jason A. Williams; Harry C. Dietz; Philip J. Spevak; Vincent L. Gott; Luca A. Vricella; Duke E. Cameron

BACKGROUND We compared results of the Bentall procedure with valve-sparing aortic root replacement (VSRR) for aortic root aneurysm in Marfan syndrome. METHODS Marfan syndrome patients who had the Bentall procedure or VSRR at our institution between April 1997 and September 2006 were identified. Follow-up information was obtained from hospital charts and contact with patients or their physicians. Kaplan-Meier survival and propensity score analyses were performed. RESULTS One hundred forty Marfan syndrome patients had either the Bentall procedure (n = 56) or VSRR (n = 84; 40 remodeling and 44 reimplantation). Bentall patients were older than VSRR patients (38 versus 29 years; p = 0.0001) and had more aortic dissections (16% versus 1%; p = 0.0012); more urgent/emergent surgery (20% versus 2%; p = 0.0008); larger preoperative sinus diameter (5.7 versus 5.1 cm; p = 0.0004); and more preoperative 3+/4+ aortic insufficiency (59% versus 10%; p < 0.0001). There were no operative deaths. Postoperatively, 9% Bentall patients (5 of 56) and 1% of VSRR patients (1 of 84) suffered thromboembolic events (p = 0.03). Two percent (1 of 56) of Bentall patients required reoperation on the aortic root versus 6% of VSRR patients (5 of 84; p = 0.40). Eight-year freedom from aortic valve replacement was 90% for VSRR patients. Eight-year survival was 90% for Bentall and 100% for VSRR patients (p = 0.01). Propensity-adjusted regression showed that the Bentall procedure did not predict mortality (p = 1.00) and did not protect from reoperation (odds ratio = 0.28; 95% confidence interval: 0.01 to 4.33; p = 0.36). CONCLUSIONS The Bentall procedure and VSRR have similar operative results in Marfan syndrome. The procedures are distinguished by higher rates of thromboembolism among Bentall patients and higher rates of reoperation among VSRR patients. Lower late survival among Bentall patients probably reflects the preferential use of the Bentall procedure for higher risk patients.


Circulation | 2005

Aortic Valve Replacement and Concomitant Mitral Valve Regurgitation in the Elderly Impact on Survival and Functional Outcome

Christopher J. Barreiro; Nishant D. Patel; Torin P. Fitton; Jason A. Williams; Pramod Bonde; Vincent Chan; Diane E. Alejo; Vincent L. Gott; William A. Baumgartner

Background—The impact of mitral regurgitation (MR) on elderly patients (≥70 years) undergoing isolated aortic valve replacement (AVR) is not clearly defined. This study investigates the long-term effects of preoperative, moderate MR on survival and functional outcome in elderly AVR patients. Methods and Results—A retrospective review identified 408 consecutive elderly patients who underwent isolated AVR from January 1983 to February 2004. The pathologic etiology of MR was determined on preoperative echocardiogram, and patients were stratified into no/mild MR (Group I; n =338) versus moderate MR (Group II; n =70). Follow-up was 95.1% complete. Functional outcome was evaluated using the Short Form-12 questionnaire. On univariate analysis, Groups I and II differed in incidence of previous myocardial infarction (13.9% versus 28.6%; P=0.004), hyperlipidemia (18.7% versus 33.3%; P=0.009), and congestive heart failure (50.0% versus 70.0%; P=0.002). On multivariate analysis, moderate MR was an independent risk factor impacting long-term survival (P=0.04). Actuarial survival at 1, 5, and 10 years for Group I was 93.8%, 73.3%, and 40.1% versus 92.3%, 58.2%, and 14.6% for Group II (P=0.04). Available postoperative echocardiograms for Group II (n =37) demonstrated improvement in MR in 81.8% of functional MR patients. However, MR persisted or worsened in 65.4% of patients with intrinsic mitral valve disease (myxomatous, calcific, or ischemic MR). Functional outcomes showed 77% of Group I versus 78.6% of Group II rated their health as good to excellent post-AVR. Conclusions—Moderate MR is an independent risk factor impacting long-term survival in elderly patients undergoing AVR. Therefore, patients with intrinsic mitral valve disease should be considered for concomitant MV surgery.


Journal of Cardiac Surgery | 2009

EuroSCORE Predicts Short- and Mid-Term Mortality in Combined Aortic Valve Replacement and Coronary Artery Bypass Patients

Kimiyoshi J. Kobayashi; Jason A. Williams; Lois U. Nwakanma; Eric S. Weiss; Vincent L. Gott; William A. Baumgartner; John V. Conte

Abstract  Background and Aim of the Study: European system for cardiac operative risk evaluation (EuroSCORE) has been studied for its effectiveness in predicting operative mortality, and more recently, long‐term mortality in a wide variety of cardiac surgical procedures. Combined coronary artery bypass and aortic valve replacement (AVR‐CABG) carries increased perioperative risk, and tends to have higher‐risk patients. Performance of the EuroSCORE system in patients undergoing concomitant AVR‐CABG has not been well established. Thus, we aimed to analyze the accuracy of both additive and logistic EuroSCOREs in predicting operative and mid‐term mortality. Methods: We retrospectively reviewed and calculated EuroSCOREs for all patients who underwent AVR‐CABG between January 2000 and December 2004. Patients who had previous cardiac surgery and those undergoing any concomitant procedures were excluded. Areas under the receiver operator curves (ROC) were determined to assess EuroSCOREs accuracy in predicting operative mortality. Kaplan‐Meier analysis and Cox regression were used to determine mid‐term survival, freedom from repeat revascularization, and predictors of these outcomes. Results: There were 233 patients who met study criteria. Mean follow‐up period was 2.2 ± 1.7 years with one patient lost to follow‐up. Mean additive and logistic EuroSCOREs were 8.77 and 16.1, respectively, with an observed mortality of 9.44%. The area under the ROC curves for additive EuroSCORE was 0.76 and for logistic EuroSCORE was 0.75. Regression analysis revealed additive EuroSCORE, but not logistic EuroSCORE, to be predictive of mid‐term mortality. Conclusions: Both additive and logistic EuroSCOREs were accurate in predicting operative morality. Only additive EuroSCORE was predictive of mid‐term mortality in AVR‐CABG patients. EuroSCORE remains a good and well‐validated risk stratification model applicable to patients who undergo concomitant AVR‐CABG.


The Annals of Thoracic Surgery | 2008

Pretransplant panel reactive antibodies in human lung transplantation: an analysis of over 10,000 patients.

Ashish S. Shah; Lois U. Nwakanma; Christopher E. Simpkins; Jason A. Williams; David C. Chang; John V. Conte

BACKGROUND The role of panel reactive antibody (PRA) in lung transplant recipients has not been clearly defined in a large population. We sought to determine how panel reactive antibody level affects survival in lung transplant recipients. METHODS The United Network for Organ Sharing (UNOS) Standard Transplant Analysis and Research files from 1987 through 2005 were analyzed. Demographic data, pretransplant PRA, relevant clinical indicators, and survival were examined. RESULTS Of the 12,751 first lung transplant recipients during this period, pretransplant PRA levels were reported for 10,237 patients. Panel reactive antibody was more than 0% in 1748 patients; of these, PRA was 1% to 10% in 1259 (72%), 11% to 25% in 249 (14%), and more than 25% in 240 (14%). Using the Kaplan-Meier method, survival decreased with increasing PRA and was significant when PRA exceeded 25% compared with the rest of the cohort. On multivariable analysis, PRA was associated with increased 30-day (hazard ratio, 2.6) and overall mortality (hazard ratio, 1.3). Importantly, this effect was not seen when a cohort from 1998 through 2005 was analyzed. CONCLUSIONS The UNOS database has provided the largest series of lung transplant patients stratified by PRA. Our analysis demonstrates that PRA level exceeding 25% is a predictor of death. However, newer laboratory and management techniques may attenuate this effect with better outcomes in the modern era.


The Journal of Thoracic and Cardiovascular Surgery | 2009

Long-acting oral phosphodiesterase inhibition preconditions against reperfusion injury in an experimental lung transplantation model

Eric S. Weiss; Hunter C. Champion; Jason A. Williams; William A. Baumgartner; Ashish S. Shah

OBJECTIVES Ischemia-reperfusion injury remains a devastating complication of lung transplantation. Phosphodiesterase inhibitors have been shown to precondition tissues against ischemia-reperfusion injury. Little is known, however, about the utility of phosphodiesterase inhibition in reperfusion injury after lung transplantation. We evaluated the long-acting phosphodiesterase-5 inhibitor, tadalafil, in an ex vivo lung transplant model. METHODS New Zealand White rabbits (4 kg), were given oral tadalafil (n = 11) 24 hours before lung harvest and compared with rabbits given oral vehicle alone (n = 11). Lungs were recovered with Perfadex solution (Vitrolife, Kungsbacka, Sweden) and cold stored for 18 hours. After storage, lung blocks were reperfused with donor rabbit blood in an ex vivo apparatus. Pulmonary artery pressures were recorded with serial arterial and venous blood gas sampling and animals served as their own controls. Phosphodiesterase-5 and protein kinase G tissue activity assays confirmed drug effects. Luminol chemiluminescence assay was used to measure reactive oxygen species and levels of endothelial and inducible nitric oxide synthase were measured. RESULTS Extended cold storage, followed by reperfusion produced a consistent reproducible decrease in oxygenation and increase in pulmonary pressure. Tadalafil-treated animals exhibited greater Pao(2) throughout the course of reperfusion (P = .001) Mean pulmonary artery pressure was lower in tadalafil-treated animals (22 vs 40 mm Hg; P = .04). Phosphodiesterase-5 activity was decreased (143 +/- 8 vs 205 +/- 32 mP; P < .001) with protein kinase G activity increased (25 +/- 12 vs 12 +/- 2.4 fU/microg; P = .01) in the experimental group confirming that oral pretreatment resulted in active phosphodiesterase inhibition in the lung tissue. Reactive oxygen species (as measured by luminol activity) were decreased in tadalafil-treated animals (7.8 +/- 1.5 vs 10.2 +/- 1.2 relative light units; P = .003). CONCLUSIONS Our experimental model demonstrates that oral donor pretreatment with a long-acting phosphodiesterase inhibitor is an effective strategy for improving pulmonary performance after reperfusion. Importantly, phosphodiesterase enzymes and their downstream effectors may play a critical role in reperfusion injury after lung transplantation.


Journal of Cardiac Failure | 2008

Surgical Ventricular Restoration Versus Cardiac Transplantation: A Comparison of Cost, Outcomes, and Survival

Jason A. Williams; Eric S. Weiss; Nishant D. Patel; Lois U. Nwakanma; Brigitte Reeb; John V. Conte

BACKGROUND Cardiac transplantation is the accepted standard treatment for end-stage heart disease but is donor limited. Surgical ventricular remodeling is an established treatment for patients with ischemic cardiomyopathy. We sought to compare charges, outcomes, and survival in patients undergoing surgical ventricular restoration (SVR) versus cardiac transplantation (CTx). METHODS AND RESULTS We retrospectively analyzed hospital charges, length of stay (LOS), and survival for 69 SVR and 53 CTx patients at our institution between January 2002 and June 2005. We also compared New York Heart Association (NYHA) status and Kaplan-Meier survival of our SVR patients with CTx patients with ischemic cardiomyopathy from the International Society of Heart & Lung Transplantation (ISHLT) registry. Median total LOS (12 days vs. 17 days, P = .01) and median postoperative LOS (10 days vs. 15 days, P = .02) were shorter for SVR patients than our CTx patients. Median total hospital charges (


The Annals of Thoracic Surgery | 2007

Early Surgical Experience With Loeys-Dietz: A New Syndrome of Aggressive Thoracic Aortic Aneurysm Disease

Jason A. Williams; Bart Loeys; Lois U. Nwakanma; Harry C. Dietz; Philip J. Spevak; Nishant D. Patel; Katrien François; Julie DeBacker; Vincent L. Gott; Luca A. Vricella; Duke E. Cameron

45,506 vs.


The Annals of Thoracic Surgery | 2007

Influence of Pretransplant Panel-Reactive Antibody on Outcomes in 8,160 Heart Transplant Recipients in Recent Era

Lois U. Nwakanma; Jason A. Williams; Eric S. Weiss; Stuart D. Russell; William A. Baumgartner; John V. Conte

137,679, P < .0001) and median total drug charges (


The Annals of Thoracic Surgery | 2007

Two thousand Blalock-Taussig shunts: a six-decade experience.

Jason A. Williams; Anshuman K. Bansal; Bradford J. Kim; Lois U. Nwakanma; Nishant D. Patel; Akhil K. Seth; Diane E. Alejo; Vincent L. Gott; Luca A. Vricella; William A. Baumgartner; Duke E. Cameron

2,625 vs.

Collaboration


Dive into the Jason A. Williams's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

John V. Conte

Johns Hopkins University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Eric S. Weiss

Johns Hopkins University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Duke E. Cameron

Howard Hughes Medical Institute

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge